The present positioning collar invention is particularly suitable for use in, for example, a high tension cable stringing apparatus such as that described in Sauber Application Ser. No. 721,035, Improvement in Reel Brake Connection Apparatus, now abandoned. In my abovesaid Application Ser. No. 721,035 there is described high tension cable stringing apparatus comprising, in general, a pair of spaced upright columns terminating in generally U-shaped ends which support a shaft adapted to receive the cable reel for rotation therewith and to bridge the column U-shaped ends. A brake device supported adjacent to one of the columns has a coupling member facing the U-shaped end of the column. The reel support shaft has a mutually engageable coupling member at its end directed to the brake device. The coupling members provide quick connection by way of a rib and slot arrangement adapted to slidably mate when the support shaft is vertically placed over the U-shaped column ends.
In operation clamping devices may be placed in abutting relationship to the cable reel for the purpose of preventing the cable reel from sliding axially in an undesirable manner.
In high tension wire stringing, wire discharged from a cable reel, at a desired and controlled rate, is strung across utility poles. During stringing if any axial movement of the cable reel occurs it can cause flapping of the high tension wire as it is being discharged from the cable reel. Flapping of the wire being put up can result in contact with existing wire and even breakage thereof, possibly causing great harm to persons and property.
It has thus been an objective of the art to devise clamping devices that will eliminate wire flapping while, in addition, enabling easy loading and unloading of the cable reel or spool when the wire thereon has been expired. The commonly known clamping devices heretofore utilized have been collar-like structures provided with set screw arrangements that permit adjustable fixing with respect to the axle. There are numerous disadvantages and shortcomings which have been encountered with the set-screw device. For example, the set screws may get separated from the clamping body or, because they have to be tightened and loosened with a wrench, corroded or damaged threads may impair the ability to secure or release the set screw. Moreover, because a wrench is needed to tighten and loosen the set screws, changing the cable reels during operation is slow and tedious and generally undesirable. Similar problems have been encountered with split collar clamping devices utilizing nut and bolt to clamp it to the shaft.
A solution to these problems was presented by the clamping device of my above mentioned prior application Ser. No. 939,243 in that it was easily mounted on, removed from and positioned on an axle supporting a cable reel as well as being fairly inexpensive to manufacture and devoid of separable parts. This was achieved by an annular collar having a central longitudinal opening adapted to receive an axle or shaft and an intersecting transverse opening which received a shiftable, captively mounted lock pin. The lock pin had a tapered surface portion which when moved in one direction affected an interference fit with the shaft and when moved in the opposite direction formed a clearance allowing the collar to be moved easily along the shaft. Other similar devices were found to have been disclosed in German Pat. No. 671,920; U.S. Pat. Nos. 1,408,993; 2,627,431; 302,519; 291,728; 1,458,802, 2,785,814; and Swedish Pat. No. 124,927, all cited in the file of my abandoned application Ser. No. 939,243.